As a result of their clonal origin, lymphoid tumors present as tumor-specific antigens unique cell surface epitopes related their recognition structures. We have produced lymphoma-specific monoclonal antibodies and demonstrated that the target structure, a disulfide-bonded heterodimer, is the T cell antigen specific receptor. Nearest-neighbor analysis of the receptor using chemical cross-linkers demonstrated that the receptor is part of a multichain complex. Recently, we have identified another heterodimer on the surface of T lymphoma cells. This molecule is serologically distinct from the alpha/beta antigen receptor and may represent a new family of T cell specific cell surface molecule. Our current goals are (1) to use conventional methods and recombinant DNA technology to produce additional antibodies to the components of the T cell receptor complex, (2) to evaluate their efficacy in specific immunotherapy, and (3) to further characterize the novel T cell heterodimer and determine its relationship to the T cell antigen receptor.